Airtight lids for product packaging are known, but they are not suitable for being connected for example to a container which is easily deformable, nor with two different containers.
Lids of this type comprise a single element and form a seal with the opening of the container to which they are applied. Such a joining operation has the drawback that, when the container is deformed, the airtightness of the closure is not guaranteed. Moreover, if the wrapper containing the product is inserted inside an outer container, it is difficult to remove the product from the inner container. In both cases, however, it is necessary to separate the lid from the container in order to open the resultant packaging and this involves a certain inconvenience during use.
Other currently known lid assemblies which can be opened do not have, on the other hand, a good degree of airtightness on account of the imperfect adhesion between the respective walls of the movable part and of the fixed part joined together, which is sufficient to cause the aforementioned loss of airtightness.